Aquaponics is similar to hydroponics but with many more benefits. It is a system where fish provide nutrients to the plants instead of chemicals. This can be done on any scale large or small.
http://www.youtube.com/watch?v=DqS9ZXUPz2k
Great post! I actually lived in Hawaii with my wife for six months backpacking around. We spent three months on the least populated island on a permaculturalist farm. Fresh bananas, coconut, papaya, mango, you name it. With a decent herb garden and banana trees everywhere he was able to feed his family, if he added a aquaponics he could easily sell produce. He may have had about an acre of land. (That said, he would have hiking trails to the jungle where there would be mango, papaya, etc, and the beach had coconuts)